Method for estimating thermal sensation, thermal sensation estimation apparatus, air conditioner, and recording medium

ABSTRACT

A vehicle including an air conditioner and a thermal sensation estimation apparatus is disclosed. The thermal sensation estimation apparatus includes a processor and a memory that stores a program, which causes the processor to perform a set of operations. The operations include obtaining thermal environment information at least regarding a thermal environment of or around a person, and estimating first and second thermal sensations using first and second methods, respectively, on the basis of the thermal environment information. The operations further include selecting at least one of the first thermal sensation estimated using the first method and the second thermal sensation estimated using the second method, and outputting, to the air conditioner, instruction information using the selected at least one of the first thermal sensation and the second thermal sensation.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation application of U.S. patent application Ser. No.15/626,392, filed Jun. 19, 2017, which claims the benefit of JapanesePatent Application No. 2016-125943, filed Jun. 24, 2016, and JapanesePatent Application No. 2016-243151, filed Dec. 15, 2016. The entiredisclosure of each of the above-identified applications, including thespecification, drawings, and claims, is incorporated herein by referencein its entirety.

BACKGROUND 1. Technical Field

The present disclosure relates to a method for estimating thermalsensation, a thermal sensation estimation apparatus, an air conditioner,and a recording medium.

2. Description of the Related Art

A thermal sensation estimation apparatus that estimates thermalsensation, which indicates a degree of warmth or coldness of a person,without a report from the person is known. When the thermal sensationestimation apparatus is installed in an automobile, for example, anautomotive air conditioner can be efficiently operated by controllingthe air temperature of the automotive air conditioner or the like on thebasis of the estimated thermal sensation.

One of thermal sensation estimation apparatuses in examples of therelated art is one that estimates thermal sensation by measuring anaverage skin temperature of a person on the basis of a fact that theaverage skin temperature and the thermal sensation have a highcorrelation. When this kind of thermal sensation estimation apparatus isused, however, a temperature sensor needs to be directly attached to aperson's skin, which is not practical.

In order to solve the above problem, a thermal sensation estimationapparatus that focuses upon the amount of heat lost from a person's skinthrough clothes has been proposed (e.g., refer to InternationalPublication No. 2015/122201). The thermal sensation estimation apparatusaccording to International Publication No. 2015/122201 calculates theamount of heat lost from a person on the basis of a difference between ahuman body surface temperature measured by a thermal camera and anatmospheric temperature (air temperature) and estimates thermalsensation on the basis of the calculated amount of heat lost from theperson.

SUMMARY

In one general aspect, the techniques disclosed here feature a methodused by a thermal sensation estimation apparatus that estimates thermalsensation, which indicates a degree of warmth or coldness of a person.The method includes obtaining thermal environment information at leastregarding a thermal environment of or around a person, selecting (1) amethod for estimating a first thermal sensation, (2) a method forestimating a second thermal sensation, or (3) both the method forestimating the first thermal sensation and the method for estimating thesecond thermal sensation as the method for estimating thermal sensation,which indicates a degree of warmth or coldness of the person, on thebasis of the thermal environment information, and estimating the thermalsensation using the selected method.

With the method for estimating thermal sensation according to the aspectof the present disclosure, thermal sensation can be accurately estimatedin accordance with a thermal environment.

It should be noted that general or specific aspects may be implementedas a system, a method, an integrated circuit, a computer program, acomputer-readable recording medium such as a compact disc read-onlymemory (CD-ROM), or any selective combination thereof.

Additional benefits and advantages of the disclosed embodiments willbecome apparent from the specification and drawings. The benefits and/oradvantages may be individually obtained by the various embodiments andfeatures of the specification and drawings, which need not all beprovided in order to obtain one or more of such benefits and/oradvantages.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating a use case of a thermal sensationestimation apparatus according to a first embodiment;

FIG. 2 is a block diagram illustrating the configuration of the thermalsensation estimation apparatus according to the first embodiment;

FIG. 3 is a flowchart illustrating a procedure of the operation of thethermal sensation estimation apparatus according to the firstembodiment;

FIG. 4 is a diagram illustrating a use case of a thermal sensationestimation apparatus according to a second embodiment;

FIG. 5 is a block diagram illustrating the configuration of the thermalsensation estimation apparatus according to the second embodiment;

FIG. 6A is a graph illustrating a relationship between thermal sensationestimated on the basis of the amount of heat transferred to a whole bodyof a subject and thermal sensation reported by the subject;

FIG. 6B is a graph illustrating a relationship between thermal sensationestimated on the basis of the amount of heat transferred to the wholebody of the subject and thermal sensation reported by the subject; and

FIG. 7 is a flowchart illustrating a procedure of the operation of thethermal sensation estimation apparatus according to the secondembodiment.

DETAILED DESCRIPTION

Underlying Knowledge Forming Basis of Present Disclosure

A method for estimating thermal sensation used by a thermal sensationestimation apparatus according to International Publication No.2015/122201 presupposes that the amount of heat lost from a person andthe person's thermal sensation have a high correlation. The person'sthermal sensation, however, does not always changes in accordance withthe amount of heat lost from the person. In a thermal environment inwhich the amount of heat lost from the person and the person's thermalsensation do not have a correlation, it is difficult to accuratelyestimate the person's thermal sensation.

In addition, in the method for estimating thermal sensation used by thethermal sensation apparatus according to International Publication No.2015/122201, the amount of heat lost from a person's skin throughclothes is calculated by measuring a temperature of a surface of theclothes using a thermal camera. Depending on a state of the surface ofthe clothes, however, the calculated amount of heat lost might include alarge error, and thermal sensation is not accurately estimated.

The present disclosure, therefore, provides a method for estimatingthermal sensation, a thermal sensation estimation apparatus, an airconditioner, and a recording medium capable of accurately estimatingthermal sensation in accordance with a thermal environment.

A method for estimating thermal sensation according to an aspect of thepresent disclosure is a method used by a thermal sensation estimationapparatus. The method includes obtaining thermal environment informationat least regarding a thermal environment of or around a person,selecting (1) a method for estimating a first thermal sensation, (2) amethod for estimating a second thermal sensation, or (3) both the methodfor estimating the first thermal sensation and the method for estimatingthe second thermal sensation as the method for estimating thermalsensation, which indicates a degree of warmth or coldness of the person,on the basis of the thermal environment information, and estimating thethermal sensation using the selected method.

According to this aspect, thermal sensation can be accurately estimatedin accordance with a thermal environment by estimating the thermalsensation using the method for estimating the first thermal sensationand/or the method for estimating the second thermal sensation selectedin accordance with the thermal environment.

For example, the method for estimating the first thermal sensation maybe a method for estimating thermal sensation based on an amount of heatlost from the person. The method for estimating the second thermalsensation may be a method for estimating thermal sensation based on asurface temperature of the person.

According to this aspect, the method for estimating the first thermalsensation based on the amount of heat lost from a person and/or themethod for estimating the second thermal sensation based on a surfacetemperature of a person can be selected in accordance with a thermalenvironment. As a result, thermal sensation can be accurately estimatedin accordance with the thermal environment.

For example, the thermal environment information may be a differencebetween a temperature outside a room in which the person stays and atemperature inside the room.

According to this aspect, a difference between a temperature outside aroom and a temperature inside the room can be used as thermalenvironment information.

For example, the method may further include determining whether thedifference is equal to or larger than a first threshold and selecting,if the difference is equal to or larger than the first threshold, themethod for estimating the second thermal sensation until a certainperiod of time elapses after the person enters the room and thenselecting the method for estimating the first thermal sensation when thecertain period of time elapses.

According to this aspect, if the difference is equal to or larger thanthe first threshold, the amount of heat lost from a surface of clothesis not equal to the amount of heat lost from skin in a thermalenvironment until a certain period of time elapses after a person entersa room, and the method for estimating the second thermal sensation isselected. If the difference is equal to or larger than the firstthreshold, the amount of heat lost from the skin is equal to the amountof heat lost from the surface of the clothes in the thermal environmentafter the certain period of time elapses, and the method for estimatingthe first thermal sensation is selected. As a result, thermal sensationcan be accurately estimated in accordance with a thermal environment.

For example, the method may further include determining whether thedifference is equal to or larger than a first threshold, furtherdetermining, if the difference is equal to or larger than the firstthreshold, whether a difference between the surface temperature of theperson and the temperature inside the room is equal to or larger than asecond threshold, and selecting, if the difference between the surfacetemperature of the person and the temperature inside the room is equalto or larger than the second threshold, the method for estimating thesecond thermal sensation or selecting, if the difference between thesurface temperature of the person and the temperature inside the room issmaller than the second threshold, the method for estimating the firstthermal sensation.

According to this aspect, if the difference is equal to or larger thanthe first threshold and a difference between a surface temperature of aperson and a temperature inside a room is equal to or larger than thesecond threshold, the amount of heat lost from a surface of clothes isnot equal to the amount of heat lost from skin in a thermal environment,and the method for estimating the second thermal sensation is selected.If the difference is equal to or larger than the first threshold and thedifference between the surface temperature of the person and thetemperature inside the room is smaller than the second threshold, theamount of heat lost from the surface of the clothes is equal to theamount of heat lost from the skin in the thermal environment, and themethod for estimating the first thermal sensation is selected. As aresult, thermal sensation can be accurately estimated in accordance witha thermal environment.

For example, the thermal environment information may be a surfacetemperature of the person's feet. Whether the surface temperature of theperson's feet is equal to or higher than a third threshold may bedetermined. If the surface temperature of the person's feet is equal toor higher than the third threshold, the method for estimating the firstthermal sensation is selected, and if the surface temperature of theperson's feet is lower than the third threshold, the method forestimating the second thermal sensation may be selected.

According to this aspect, if a surface temperature of feet is equal toor higher than the third threshold, thermal sensation according to theamount of heat lost from a person is obtained, and the method forestimating the first thermal sensation is selected. If the surfacetemperature of the feet is lower than the third threshold, thermalsensation according to the amount of heat lost from the person is notobtained, and the method for estimating the second thermal sensation isselected. As a result, thermal sensation can be estimated in accordancewith a thermal sensation.

For example, the thermal environment information may be a temperaturearound the person's feet. Whether the temperature around the person'sfeet is equal to or higher than a fourth threshold may be determined. Ifthe temperature around the person's feet is equal to or higher than thefourth threshold, the method for estimating the first thermal sensationmay be selected, and if the temperature around the person's feet islower than the fourth threshold, the method for estimating the secondthermal sensation may be selected.

According to this aspect, if a temperature around feet is equal to orhigher than the fourth threshold, thermal sensation according to theamount of heat lost from a person is obtained, and the method forestimating the first thermal sensation is selected. If the temperaturearound the feet is lower than the fourth threshold, thermal sensationaccording to the amount of heat lost from the person is not obtained,and the method for estimating the second thermal sensation is selected.As a result, thermal sensation can be accurately estimated in accordancewith a thermal environment.

For example, the thermal environment information may be a surfacetemperature of the person's hands. Whether the surface temperature ofthe person's hands is equal to or higher than a fifth threshold may bedetermined. If the surface temperature of the person's hands is equal toor higher than the fifth threshold, the method for estimating the firstthermal sensation may be selected, and if the surface temperature of theperson's hands is lower than the fifth threshold, the method forestimating the second thermal sensation may be selected.

According to this aspect, if a surface temperature of hands is equal toor higher than the fifth threshold, thermal sensation according to theamount of heat lost from a person is obtained, and the method forestimating the first thermal sensation is selected. If the surfacetemperature of the hands is lower than the fifth threshold, thermalsensation according to the amount of heat lost from the person is notobtained, and the method for estimating the second thermal sensation isselected. As a result, thermal sensation can be accurately estimated inaccordance with a thermal environment.

For example, the method for estimating the first thermal sensation maybe performed by calculating a difference between a surface temperatureof a human body area, which at least includes a part of the person'sbody exposed and a part of the person's clothes, and a temperaturearound the person, calculating an amount of heat lost from the person bymultiplying the difference by a certain value, and estimating thethermal sensation on the basis of the amount of heat lost from theperson.

According to this aspect, thermal sensation can be easily estimated onthe basis of the amount of heat lost from a person.

For example, the surface temperature of the human body area may becalculated using a thermal image of an area including the personcaptured by a thermal camera.

According to this aspect, a surface temperature of a human body area canbe easily calculated using a thermal image.

For example, the method for estimating the second thermal sensation maybe performed by obtaining a surface temperature of a human body area,which at least includes a part of the person's body exposed and a partof the person's clothes, and estimating the thermal sensation on thebasis of a result of a comparison between the surface temperature of thehuman body area and a sixth threshold.

According to this aspect, thermal sensation can be easily estimated onthe basis of a surface temperature of a person.

For example, the surface temperature of the human body area may becalculated using a thermal image of an area including the personcaptured by a thermal camera.

According to this aspect, a surface temperature of a human body area canbe easily calculated using a thermal image.

For example, the person may be inside a vehicle, and the thermalenvironment around the person may be at least either an outside or aninside of the vehicle.

According to this aspect, in a thermal environment in which a person isinside a vehicle, for example, thermal sensation can be accuratelyestimated.

For example, the estimation of the thermal sensation using both themethod for estimating the first thermal sensation and the method forestimating the second thermal sensation may be performed byweight-averaging a result of estimation of thermal sensation by themethod for estimating the first thermal sensation and a result ofestimation of thermal sensation by the method for estimating the secondthermal sensation using a certain value.

According to this aspect, thermal sensation can be estimated moreaccurately.

For example, instruction information for controlling air volume, airtemperature, or wind direction of an air conditioner may be output tothe air conditioner on the basis of the estimated thermal sensation.

According to this aspect, the air conditioner can be controlled suchthat, for example, thermal sensation becomes close to a neutral value.As a result, the air conditioner does not cool or heat too much, andpower is saved.

A thermal sensation estimation apparatus according to an aspect of thepresent disclosure includes a processor and a memory that stores acomputer program. The program causes the processor to perform operationsincluding: obtaining thermal environment information at least regardinga thermal environment of or around a person; selecting (1) a method forestimating a first thermal sensation, (2) a method for estimating asecond thermal sensation, or (3) both the method for estimating thefirst thermal sensation and the method for estimating the second thermalsensation as the method for estimating thermal sensation, whichindicates a degree of warmth or coldness of the person, on the basis ofthe thermal environment information; and estimating the thermalsensation using the selected method.

According to this aspect, thermal sensation can be accurately estimatedin accordance with a thermal environment by estimating the thermalsensation using the method for estimating the first thermal sensationand/or the method for estimating the second thermal sensation selectedin accordance with the thermal environment.

An air conditioner according to an aspect of the present disclosureincludes the thermal sensation estimation apparatus. Air volume, airtemperature, or wind direction is controlled on the basis of thermalsensation estimated by the thermal sensation estimation apparatus.

According to this aspect, the air conditioner can be controlled suchthat, for example, thermal sensation becomes close to a neutral value.As a result, the air conditioner does not cool or heat too much, andpower is saved.

A non-transitory recording medium according to an aspect of the presentdisclosure is a non-transitory recording medium storing a program forcausing a computer to function as a thermal sensation estimationapparatus. The program causes the computer to perform operationsincluding obtaining thermal environment information at least regarding athermal environment of or around a person, selecting (1) a method forestimating a first thermal sensation, (2) a method for estimating asecond thermal sensation, or (3) both the method for estimating thefirst thermal sensation and the method for estimating the second thermalsensation as the method for estimating thermal sensation on the basis ofthe thermal environment information, and estimating thermal sensation,which indicates a degree of warmth or coldness of the person, using theselected method.

According to this aspect, thermal sensation can be accurately estimatedin accordance with a thermal environment by estimating the thermalsensation using the method for estimating the first thermal sensationand/or the method for estimating the second thermal sensation selectedin accordance with the thermal environment.

It should be noted that these general or specific aspects may beimplemented as a system, a method, an integrated circuit, a computerprogram, a computer-readable recording medium such as a compact discread-only memory (CD-ROM), or any selective combination thereof.

Embodiments will be specifically described hereinafter with reference tothe drawings.

The following embodiments are general or specific examples. Values,shapes, materials, components, arrangement positions and connectionmodes of the components, steps, the order of the steps, and the likementioned in the following embodiments are examples, and do not limitthe present disclosure. Among the components described in the followingembodiments, ones not described in the independent claims, which definebroadest concepts, will be described as arbitrary components.

First Embodiment

1-1. Configuration of Thermal Sensation Estimation Apparatus

First, the configuration of a thermal sensation estimation apparatus 10according to a first embodiment will be described with reference toFIGS. 1 and 2. FIG. 1 is a diagram illustrating a use case of thethermal sensation estimation apparatus 10 according to the firstembodiment. FIG. 2 is a block diagram illustrating the configuration ofthe thermal sensation estimation apparatus 10 according to the firstembodiment.

As illustrated in FIG. 1, for example, the thermal sensation estimationapparatus 10 is installed in an inside of a vehicle body 201 (an exampleof an inside of a room) of an automobile 20 (an example of a vehicle).When, in winter (or summer), a person 30 gets in the vehicle body 201 inwhich a heating operation (or a cooling operation) is being performed,for example, the thermal sensation estimation apparatus 10 estimatesthermal sensation of the person 30 (a driver or the like) in a seat 202of the automobile 20. As described later, the thermal sensationestimated by the thermal sensation estimation apparatus 10 is used tocontrol air volume, air temperature, or wind direction of an automotiveair conditioner 40.

As illustrated in FIG. 1, the automotive air conditioner 40 cools orheats the air inside the vehicle body 201 of the automobile 20. Theautomotive air conditioner 40 blows cold air to an upper half of a bodyof the person 30 in a cooling operation and blows warm air to the upperhalf of the body and feet of the person 30 in a heating operation.

As illustrated in FIGS. 1 and 2, the thermal sensation estimationapparatus 10 includes a first thermal camera 101, a second thermalcamera 102, a first thermal sensation estimation unit 103, a secondthermal sensation estimation unit 104, an inside temperature sensor 105,an outside temperature sensor 106, a thermal sensation estimation methoddetermination unit 107, and a control unit 108.

The first thermal camera 101 and the second thermal camera 102 detectinfrared light radiated from objects and obtain thermal imagesindicating thermal distribution in space. As illustrated in FIG. 1, thefirst thermal camera 101 is mounted on a dashboard of the vehicle body201, for example, and captures a thermal image of a lower half of thebody of the person 30 in the seat 202 from the front. The second thermalcamera 102 is mounted on a rearview mirror of the vehicle body 201, forexample, and captures a thermal image of the upper half of the body ofthe person 30 in the seat 202 from the front. The first thermal camera101 and the second thermal camera 102 combine a thermal image of thelower half of the body of the person 30 and a thermal image of the upperhalf of the body of the person 30 captured from the front to obtain athermal image of an area including the whole body of the person 30viewed from the front.

The first thermal sensation estimation unit 103 estimates the thermalsensation of the person 30 using a method for estimating a first thermalsensation based on the amount of heat lost from the person 30. The firstthermal sensation estimation unit 103 includes a heat loss calculationsection 109 and a thermal sensation estimation section 110.

The heat loss calculation section 109 calculates the total amount ofheat lost to an outside from the whole body of the person 30. Ingeneral, the person 30 loses heat to the outside through a) convection(includes conduction), b) radiation, and c) expiration and theevaporation of perspiration. Expiration and the evaporation ofperspiration remain constant when the person 30 is at rest. The heatloss calculation section 109, therefore, calculates the amount of heatlost through convection (hereinafter referred to as the “amount of heatconvected”) and the amount of heat lost through radiation (hereinafterreferred to as the “amount of heat radiated”), which are dominantfactors in determining thermal sensation.

The amount of heat convected is the amount of heat lost throughconvection between air and the person 30. The amount of heat convectedis calculated by multiplying a difference between an average surfacetemperature of the whole body of the person 30 in a human body area anda temperature inside the vehicle body 201 (an example of a temperaturearound a person) by a convective heat transfer coefficient (an exampleof a certain value). The human body area at least includes a part of thebody of the person 30 exposed and a part of clothes of the person 30.The average surface temperature of the whole body of the person 30 isobtained from thermal images captured by the first thermal camera 101and the second thermal camera 102. The temperature inside the vehiclebody 201 is measured by the inside temperature sensor 105 installed inthe vehicle body 201. As the temperature inside the vehicle body 201, anaverage temperature of a background image, which is a part of a thermalimage other than the person 30, may be used. The convective heattransfer coefficient is a fixed value set in advance.

The amount of heat radiated is calculated by multiplying a differencebetween the average surface temperature of the whole body of the person30 in the human body area and an average radiation temperaturesurrounding the person 30 by a radiative heat transfer coefficient. Theaverage radiation temperature and the average surface temperature of thewhole body of the person 30 are obtained from thermal images captured bythe first thermal camera 101 and the second thermal camera 102. As theaverage radiation temperature, an average temperature in a backgroundimage, which is a part of a thermal image other than the person 30, maybe used. Alternatively, the average radiation temperature may beobtained using a globe thermometer (not illustrated) installed in thevehicle body 201. The radiative heat transfer coefficient is a fixedvalue set in advance.

The heat loss calculation section 109 adds the amount of heat convectedand the amount of heat radiated and then calculates the total amount ofheat lost by multiplying a result of the addition by a certain arearatio. A specific calculation method used by the heat loss calculationsection 109 will be described later.

The thermal sensation estimation section 110 estimates the thermalsensation (hereinafter referred to as a “first thermal sensation”) ofthe person 30 on the basis of the total amount of heat lost calculatedby the heat loss calculation section 109. A specific estimation methodused by the thermal sensation estimation section 110 will be describedlater.

The second thermal sensation estimation unit 104 estimates the thermalsensation (hereinafter referred to as a “second thermal sensation”) ofthe person 30 using a method for estimating a second thermal sensationbased on a surface temperature of the person 30. More specifically, thesecond thermal sensation estimation unit 104 compares the averagesurface temperature of the whole body of the person 30 in the human bodyarea with a sixth threshold. If the average surface temperature is lowerthan the sixth threshold, the second thermal sensation estimation unit104 determines that the person 30 is feeling relatively cold, and if theaverage surface temperature is equal to or higher than the sixththreshold, the second thermal sensation estimation unit 104 determinesthat the person 30 is feeling relatively warm. The average surfacetemperature of the whole body of the person 30 is obtained from thermalimages captured by the first thermal camera 101 and the second thermalcamera 102. A known technique may be used for the method for estimatingthe second thermal sensation.

As a method for estimating thermal sensation to be used, the thermalsensation estimation method determination unit 107 selects either 1) themethod for estimating the first thermal sensation or (2) the method forestimating the second thermal sensation on the basis of a difference (anexample of thermal environment information regarding a thermalenvironment around the person 30) between the temperature inside thevehicle body 201 in which the person 30 stays and a temperature of anoutside of the vehicle body 201 (an example of an outside of a room).The thermal sensation estimation method determination unit 107transmits, to the control unit 108, thermal sensation (the first thermalsensation or the second thermal sensation) estimated by the selectedmethod for estimating thermal sensation.

More specifically, if the difference is smaller than a first threshold,the thermal sensation estimation method determination unit 107 selectsthe method for estimating the first thermal sensation. If the differenceis equal to or larger than the first threshold and a difference betweenthe average surface temperature of the whole body of the person 30 inthe human body area and the temperature inside the vehicle body 201 issmaller than a second threshold, the thermal sensation estimation methoddetermination unit 107 selects the method for estimating the firstthermal sensation. If the difference is equal or larger than the firstthreshold and the difference between the average surface temperature ofthe whole body of the person 30 in the human body area and thetemperature inside the vehicle body 201 is equal to or larger than thesecond threshold, the thermal sensation estimation method determinationunit 107 selects the method for estimating the second thermal sensation.The thermal sensation estimation method determination unit 107 transmitsthe first thermal sensation or the second thermal sensation to thecontrol unit 108 depending on the selected method for estimating thermalsensation. The temperature inside the vehicle body 201 is measured bythe inside temperature sensor 105, for example, installed in the vehiclebody 201. The temperature outside the vehicle body 201 is measured bythe outside temperature sensor 106, for example, installed outside thevehicle body 201.

A criterion used by the thermal sensation estimation methoddetermination unit 107 to select a method for estimating thermalsensation will be described hereinafter. The person 30 loses heat to theoutside from the skin through the clothes. At this time, if the clothesare in a steady heat conduction state, the amount of heat lost from asurface of the clothes can be seen as equal to the amount of heat lostto the outside from the skin. The amount of heat lost from the person30, therefore, can be calculated by obtaining a difference between atemperature of the surface of the clothes and an atmospheric temperature(air temperature). If the amount of heat lost and the amount of heatproduced (the amount of metabolism) are in balance, heat balance ismaintained, and the person 30 can be estimated to be thermally neutral.If the amount of heat lost is larger than the amount of heat produced,on the other hand, it can be estimated that the person 30 is feelingrelatively cold, and if the amount of heat lost is smaller than theamount of heat produced, it can be estimated that the person 30 isfeeling relatively warm. The method for estimating the first thermalsensation based on the amount of heat lost from the person 30 is usedtherefore only when it is known that the amount of heat lost from thesurface of the clothes is the same as the amount of heat lost from theskin. In other words, when it is known that the amount of heat lost fromthe surface of the clothes is the same the amount of heat lost from theskin, the method for estimating the first thermal sensation iseffective, and the thermal sensation estimation method determinationunit 107 selects the method for estimating the first thermal sensation.

On the other hand, when the person 30 who has stayed outside wheretemperature is 0° C. enters a vehicle whose inside temperature is 20°C., for example, the temperature of the surface of the clothes hasbecome close to 0° C., and heat begins to transfer from the thermalenvironment whose temperature is 20° C. to the surface of the clotheswhose temperature is 0° C. At this time, the amount of heat lost to theoutside from the surface of the clothes is calculated as a negativevalue (heat is received), but the amount of heat lost from the skin tothe surface of the clothes whose temperature is 0° C. is calculated as apositive value (heat is lost). That is, the amount of heat lost from thesurface of the clothes and the amount of heat lost from the skin arecompletely different from each other. In this case, the method forestimating the first thermal sensation is not effective, and the thermalsensation estimation method determination unit 107 selects the methodfor estimating the second thermal sensation.

Since the thermal sensation of the person 30 depends on how the person30 is dressed, an accuracy of estimating thermal sensation achieved bythe method for estimating the second thermal sensation is not higherthan an accuracy of estimating thermal sensation achieved by the methodfor estimating the first thermal sensation. As described above, however,when the amount of heat lost from the surface of the clothes is not thesame as the amount of heat lost from the skin, the method for estimatingthe second thermal sensation reflects an actual thermal sensation morethan the method for estimating the first thermal sensation.

The control unit 108 transmits (outputs), to the automotive airconditioner 40, instruction information for controlling at least one ofthe air volume, the air temperature, and the wind direction of theautomotive air conditioner 40 on the basis of a thermal sensation (thefirst thermal sensation or the second thermal sensation) transmittedfrom the thermal sensation estimation method determination unit 107.

Some or all of the first thermal sensation estimation unit 103, thesecond thermal sensation estimation unit 104, and the thermal sensationestimation method determination unit 107 may be achieved as software bya processor (not illustrated), which is included in the thermalsensation estimation apparatus 10, that executes a program, or may beachieved as hardware by a dedicated circuit. Information used by theabove components for their respective processes is stored in a memory(not illustrated) or a storage (not illustrated) included in the thermalsensation estimation apparatus 10.

1-2. Operation of Thermal Sensation Estimation Apparatus

Next, the operation (the method for estimating thermal sensation) of thethermal sensation estimation apparatus 10 according to the firstembodiment will be described with reference to FIG. 3. FIG. 3 is aflowchart illustrating a procedure of the operation of the thermalsensation estimation apparatus 10 according to the first embodiment.

As illustrated in FIG. 3, first, the person 30 gets in the automobile 20(S101) and sits in the seat 202. The first thermal camera 101 and thesecond thermal camera 102 then capture thermal images of the whole bodyof the person 30 from the front (S102).

The heat loss calculation section 109 of the first thermal sensationestimation unit 103 then obtains an average surface temperature Td ofthe whole body of the person 30 on the basis of the thermal imagescaptured in step S102. The heat loss calculation section 109 alsoobtains a temperature Ta inside the vehicle body 201 measured by theinside temperature sensor 105 installed in the vehicle body 201. Theheat loss calculation section 109 then calculates an amount Hc of heatconvected by multiplying a difference between the average surfacetemperature Tcl of the whole body of the person 30 and the temperatureTa by a convective heat transfer coefficient hc as in expression (1)(S103).Hc=hc×(Tcl−Ta)  (1)

-   Hc: Amount of heat convected-   hc: Convective heat transfer coefficient-   Ta: Temperature-   Tcl: Average surface temperature of whole body of person

The heat loss calculation section 109 also obtains an average radiationtemperature Tr and an average surface temperature Tc of the whole bodyof the person 30 on the basis of the thermal images captured in stepS102. The heat loss calculation section 109 then calculates an amount Hrof heat radiated by multiplying a difference between the average surfacetemperature Tc of the whole body of the person 30 and the averageradiation temperature Tr by a radiative heat transfer coefficient hr asin expression (2) (S104).Hr=hr×(Tc−Tr)  (2)

-   Hr: Amount of heat radiated-   hr: Radiative heat transfer coefficient-   Tc: Average surface temperature of whole body of person-   Tr: Average radiation temperature

The heat loss calculation section 109 then adds the amount Hc of heatconvected and the amount Hr of heat radiated as in expression (3). Theheat loss calculation section 109 also calculates a total amount H ofheat lost by multiplying a result of the addition by 1−Ws, which is aratio (Wb/Wt) of an area Wb of an insulated part 301 of the person 30 (apart of the person 30 insulated by the seat 202) to an area Wt of thewhole body of the person 30, as in expression (3) (S105).H=(Hc+Hr)×(1−Ws)  (3)

-   H: Total amount of heat lost-   Ws: Ratio of area of insulated part 301 to area of whole body

The thermal sensation estimation section 110 of the first thermalsensation estimation unit 103 then estimates a first thermal sensationTs1 on the basis of the total amount H of heat lost as in expression (4)(S106). The first thermal sensation Ts1 ranges, for example, from “−4”(cold) to “+4” (hot). A central value “0” (neutral) of the first thermalsensation Ts1 indicates a comfortable state.Ts1=a×H+b  (4)

-   Ts1: First thermal sensation-   a: Coefficient-   b: Y-intercept

The second thermal sensation estimation unit 104 then obtains theaverage surface temperature Tcl of the whole body of the person 30 onthe basis of the thermal images captured in step S102. The secondthermal sensation estimation unit 104 estimates a second thermalsensation Ts2 on the basis of a difference between the average surfacetemperature Tcl and the sixth threshold (S107). As with the firstthermal sensation Tsl, the second thermal sensation Ts2 ranges, forexample, “−4” (cold) to “+4” (hot).

The thermal sensation estimation method determination unit 107 thenobtains the temperature Ta inside the vehicle body 201 measured by theinside temperature sensor 105 installed in the vehicle body 201. Thethermal sensation estimation method determination unit 107 also obtainsa temperature Tb outside the vehicle body 201 measured by the outsidetemperature sensor 106 installed outside the vehicle body 201. Thethermal sensation estimation method determination unit 107 determineswhether a difference between the temperature Ta inside the vehicle body201 and the temperature Tb outside the vehicle body 201 is equal to orlarger than the first threshold (S108).

If the difference is smaller than the first threshold (NO in S108), thethermal sensation estimation method determination unit 107 selects themethod for estimating the first thermal sensation (S109) and transmitsthe first thermal sensation Ts1 to the control unit 108 (S110). When thedifference is smaller than the first threshold, it might be possible,for example, that the person 30 who had stayed outside in spring orautumn where temperature was 20° C. has entered the vehicle body 201whose inside temperature is 20° C. and in which the automotive airconditioner 40 is not operating.

In step S108, if the difference is equal to or larger than the firstthreshold (YES in S108), the thermal sensation estimation methoddetermination unit 107 determines whether a difference between theaverage surface temperature Tcl of the whole body of the person 30 andthe temperature Ta inside the vehicle body 201 is equal to or largerthan the second threshold (S111). If the difference between the averagesurface temperature Tcl and the temperature Ta inside the vehicle body201 is smaller than the second threshold (NO in S111), the thermalsensation estimation method determination unit 107 selects the methodfor estimating the first thermal sensation (S109) and transmits thefirst thermal sensation Ts1 to the control unit 108 (S110). When thedifference between the temperature Ta and the temperature Tb is equal toor larger than the first threshold and the difference between theaverage surface temperature Tcl and the temperature Ta inside thevehicle body 201 is smaller than the second threshold, it might bepossible, for example, that the person 30 who had stayed outside inwinter where temperature was 0° C. has entered the vehicle body 201whose inside temperature is 20° C. and in which the automotive airconditioner 40 is performing a heating operation and the temperature ofthe surface of the clothes of the person 30 is about 20° C.

In step S111, if the difference between the average surface temperatureTel and the temperature Ta inside the vehicle body 201 is equal to orlarger than the second threshold (YES in S111), the thermal sensationestimation method determination unit 107 selects the method forestimating the second thermal sensation (S112) and transmits the secondthermal sensation Ts2 to the control unit 108 (S113). When thedifference between the temperature Ta and the temperature Tb is equal toor larger than the first threshold and the difference between theaverage surface temperature Tcl and the temperature Ta inside thevehicle body 201 is equal to or larger than the second threshold, itmight be possible, for example, that the person 30 who had stayedoutside in winter where temperature was 0° C. has entered the vehiclebody 201 whose inside temperature is 20° C. and the temperature of thesurface of the clothes of the person 30 is about 0° C.

The control unit 108 then transmits instruction information to theautomotive air conditioner 40 on the basis of the first thermalsensation Ts1 or the second thermal sensation Ts2 (S114). As a result,at least one of air volume, air temperature, and wind direction of theautomotive air conditioner 40 is controlled such that, for example, thefirst thermal sensation Ts1 or the second thermal sensation Ts2 becomesclose to the value (neutral value) at which the person 30 does not feelcold or hot.

1-3. Advantageous Effects

As described above, when the temperature outside the vehicle body 201 islower than the temperature inside the vehicle body 201 and thetemperature inside the vehicle body 201 is higher than the temperatureof the surface of the clothes of the person 30, for example, the amountof heat lost from the surface of the clothes is not equal to the amountof heat lost from the skin. In this case, the thermal sensationestimation method determination unit 107 selects the method forestimating the second thermal sensation based on the surface temperatureof the person 30, not the method for estimating the first thermalsensation based on the amount of heat lost from the person 30. As aresult, thermal sensation can be estimated with a certain accuracy evenin an environment where it is difficult to accurately estimate thethermal sensation with the method for estimating the first thermalsensation.

In addition, since the thermal sensation estimation apparatus 10 isinstalled in the automobile 20, for example, the automotive airconditioner 40 can be controlled such that the thermal sensation becomesclose to a value at which the person 30 does not feel cold or hot. As aresult, the automotive air conditioner 40 does not cool or heat toomuch, and power is saved. The power that would otherwise be consumed bythe automotive air conditioner 40, therefore, can be used to drive theautomobile 20, and the automobile 20 can travel a longer distance.

Although a case in which the person 30 moves from a cold environmentoutside the vehicle body 201 into the warm vehicle body 201 has beendescribed in the present embodiment, the above advantageous effects canalso be produced when the person 30 moves from a hot environment outsidethe vehicle body 201 into the cool vehicle body 201.

In addition, although the second thermal sensation estimation unit 104estimates the second thermal sensation using the average surfacetemperature of the whole body of the person 30, the method forestimating the second thermal sensation is not limited to this. Forexample, the second thermal sensation may be estimated using an averagesurface temperature of feet 302 or hands 303 of the person 30, instead.Because, when the person 30 feels cold, blood vessels in the hands 303and the feet 302 of the person 30 contract to reduce loss of heat, anaverage surface temperature of the periphery is more correlated withthermal sensation than the average surface temperature of the whole bodyis. In this case, it is desirable to directly measure the skintemperature of the periphery, but if the skin and the clothes are indirect contact, the temperature of the surface of the clothes may bemeasured, instead. Because the skin temperature of a face is relativelywell correlated with thermal sensation, the second thermal sensation maybe estimated using an average surface temperature of the face of theperson 30, instead.

In addition, although the thermal sensation estimation methoddetermination unit 107 determines in step S111 whether the differencebetween the average surface temperature Tcl of the whole body of theperson 30 and the temperature Ta inside the vehicle body 201 is equal toor larger than the second threshold in the present embodiment, theprocessing performed by the thermal sensation estimation methoddetermination unit 107 is not limited to this. If the difference isequal to or larger than the first threshold, the thermal sensationestimation method determination unit 107 may, instead of performing stepS111, select the method for estimating the second thermal sensationuntil a certain period of time elapses after the person 30 enters thevehicle body 201 and then select the method for estimating the firstthermal sensation when the certain period of time elapses. This isbecause the temperature of the surface of the clothes remains about 0°C. until the certain period of time elapses after the person 30 who hasstayed outside where temperature is 0° C. enters a vehicle whose insidetemperature is 20° C., for example, and the amount of heat lost from thesurface of the clothes is different from the amount of heat lost fromthe skin.

Second Embodiment

2-1. Configuration of Thermal Sensation Estimation Apparatus

Next, the configuration of a thermal sensation estimation apparatus 10Aaccording to a second embodiment will be described with reference toFIGS. 4 and 5. FIG. 4 is a diagram illustrating a use case of thethermal sensation estimation apparatus 10A according to the secondembodiment. FIG. 5 is a block diagram illustrating the configuration ofthe thermal sensation estimation apparatus 10A according to the secondembodiment. In the present embodiment, the same components as thoseaccording to the first embodiment are given the same reference numerals,and description thereof is omitted.

In the present embodiment, a case will be described in which theautomotive air conditioner 40 performs a heating operation in winter. Asillustrated in FIG. 4, seat heaters 203 for heating a back of the person30 are installed in the seat 202 of the automobile 20.

As illustrated in FIGS. 4 and 5, the thermal sensation estimationapparatus 10A includes heat flow meters 111 in addition to thecomponents described in the first embodiment. As illustrated in FIG. 4,the heat flow meters 111 are mounted on the seat heaters 203 and measurethe amount of heat transferred from the seat heaters 203 to the person30. Alternatively, thermometers, for example, may be mounted on the seatheaters 203 instead of the heat flow meters 111, and the amount of heattransferred may be estimated on the basis of temperatures measured bythe thermometers. Alternatively, the heat flow meters 111 may beomitted, and the amount of heat transferred may be estimated on thebasis of power (current), for example, supplied to the seat heaters 203.

A heat conduction calculation section 109A of a first thermal sensationestimation unit 103A calculates the amount of heat conducted in a seatpart 304, in which the person 30 is in contact with the seat heaters203, of the human body area. More specifically, the heat conductioncalculation section 109A calculates a reciprocal of the amount of heattransferred from the seat heaters 203 to the person 30 measured by theheat flow meters 111 as the amount of heat conducted in the seat part304.

A second thermal sensation estimation unit 104A estimates the secondthermal sensation using an average surface temperature of the feet 302of the person 30. More specifically, the second thermal sensationestimation unit 104A compares the average surface temperature of thefeet 302 with a threshold. If the average surface temperature of thefeet 302 is lower than the threshold, the second thermal sensationestimation unit 104A estimates that the person 30 is feeling relativelycold, and if the average surface temperature of the feet 302 is equal toor higher than the threshold, the second thermal sensation estimationunit 104A estimates that the person 30 is feeling relatively warm. Theaverage surface temperature of the feet 302 is obtained from thermalimages captured by the first thermal camera 101 and the second thermalcamera 102.

As a method for estimating thermal sensation to be used, a thermalsensation estimation method determination unit 107A selects either (1)the method for estimating the first thermal sensation or (2) the methodfor estimating the second thermal sensation on the basis of a result ofthe comparison between the average surface temperature of the feet 302of the person 30 (an example of thermal environment informationregarding a thermal environment of a person) and a third threshold. Morespecifically, if the average surface temperature of the feet 302 isequal to or higher than the third threshold, the thermal sensationestimation method determination unit 107A selects the method forestimating the first thermal sensation. If the average surfacetemperature of the feet 302 is lower than the third threshold, on theother hand, the thermal sensation estimation method determination unit107 selects the method for estimating the second thermal estimation. Theaverage surface temperature of the feet 302 is obtained from thermalimages captured by the first thermal camera 101 and the second thermalcamera 102.

A criterion used by the thermal sensation estimation methoddetermination unit 107A to select the method for estimating thermalsensation will be described with reference to FIGS. 6A and 6B. FIGS. 6Aand 6B are graphs illustrating relationships between thermal sensationestimated on the basis of the amount of heat transferred to a whole bodyof a subject and thermal sensation reported by the subject. Dots in acircle P in FIG. 6A are results at a time when the subject's feet arecold. Dots in a circle Q in FIG. 6B are results at a time when thesubject's feet are heated by a foot warmer.

Solid lines in FIGS. 6A and 6B indicate an ideal correlation between theestimated thermal sensation and the reported thermal sensation, which isa high correlation. As can be seen from the results in the circle P inFIG. 6A, when the subject's feet are fairly cold, the subject tends tofeel cold regardless of the amount of heat transferred (the amount ofheat received). On the other hand, as can be seen from the results inthe circle Q in FIG. 6B, after the subject's feet are heated by the footwarmer, the reported thermal sensation is well correlated with theamount of heat transferred (the amount of heat received). That is, whensomeone's feet are cold, an error in the estimation of thermal sensationbecomes large in the case of the method for estimating the first thermalsensation, and an actual thermal sensation is reflected more accuratelyif the method for estimating the second thermal sensation is used.

2-2. Operation of Thermal Sensation Estimation Apparatus

Next, the operation (the method for estimating thermal sensation) of thethermal sensation estimation apparatus 10A according to the secondembodiment will be described with reference to FIG. 7. FIG. 7 is aflowchart illustrating a procedure of the operation of the thermalsensation estimation apparatus 10A according to the second embodiment.In FIG. 7, the same steps as those according to the first embodimentillustrated in FIG. 3 are given the same reference numerals, anddescription thereof is omitted.

First, as in the first embodiment, steps S101 to S104 are performed. Theheat conduction calculation section 109A of the first thermal sensationestimation unit 103A then calculates the reciprocal of the amount ofheat transferred from the seat heaters 203 to the person 30 measured bythe heat flow meters 111 as an amount Hcd of heat conducted in the seatpart 304 (S201). The seat part 304 is a part of the human body area inwhich the person 30 is in contact with the seat heaters 203.

The heat conduction calculation section 109A then calculates the totalamount H of heat lost by weight-averaging the amount Hc of heatconvected, the amount Hr of heat radiated, and the amount Hcd of heatconducted with an area ratio Wst as in expression (5) (S202).H=(Hc+Hr)×(1−Wst)+Wst×Hcd  (5)

-   H: Total amount of heat lost-   Wst: Ratio of area of seat part 304 to area of whole body-   Hcd: Amount of heat conducted

As the first embodiment, step S106 is then performed. The second thermalsensation estimation unit 104A then estimates the second thermalsensation Ts2 on the basis of an average surface temperature Tft of thefeet 302 obtained from the thermal images captured in step S102 (S203).

The thermal sensation estimation method determination unit 107A thendetermines whether the average surface temperature Tft of the feet 302is equal to or higher than the third threshold (S204). If the averagesurface temperature Tft of the feet 302 is equal to or higher than thethird threshold (YES in S204), the thermal sensation estimation methoddetermination unit 107A selects the method for estimating the firstthermal estimation (S109) and transmits the first thermal sensation Ts1to the control unit 108 (S110). When the average surface temperature Tftof the feet 302 is equal to or higher than the third threshold, it mightbe possible, for example, that the automotive air conditioner 40 isperforming a heating operation in winter and the person 30 is heatinghis/her feet 302 with a foot warmer.

In step S204, if the average surface temperature Tft of the feet 302 islower than the third threshold (NO in S204), the thermal sensationestimation method determination unit 107A selects the method forestimating the second thermal sensation (S112) and transmits the secondthermal sensation Ts2 to the control unit 108 (S113). When the averagesurface temperature Tft of the feet 302 is lower than the thirdthreshold, it might be possible, for example, that the automotive airconditioner 40 is performing a heating operation in winter but the feet302 of the person 30 are cold.

As in the first embodiment, step S114 is then performed.

2-3. Advantageous Effects

As described above, when the person 30 is feeling cold in winterregardless of the amount of heat transferred (the amount of heatreceived) to the person 30 because the feet 302 of the person 30 arecold, for example, the thermal sensation estimation apparatus 10Aaccording to the present embodiment estimates the second thermalsensation using the method for estimating the second thermal sensationbased on the average surface temperature of the feet 302. As a result,thermal sensation can be accurately estimated even when thermalsensation according to the amount of heat transferred is not obtained.

The same advantageous effects can also be produced, for example, whenthe person 30 is not feeling cool in summer regardless of the amount ofheat lost from the person 30 because the feet 302 of the person 30 arehot.

Although the thermal sensation estimation method determination unit 107Aselects the method for estimating thermal sensation to be used on thebasis of a result of a comparison between the average surfacetemperature of the feet 302 of the person 30 and the third threshold inthe present embodiment, the thermal sensation estimation methoddetermination unit 107A may select the method for estimating thermalsensation to be used on the basis of a result of a comparison between atemperature (an example of thermal environment information regarding athermal environment around a person) around the feet 302 of the person30 and a fourth threshold, instead. In this case, if the temperaturearound the feet 302 is equal to or higher than the fourth threshold, thethermal sensation estimation method determination unit 107A selects themethod for estimating the first thermal sensation. If the temperaturearound the feet 302 is lower than the fourth threshold, on the otherhand, the thermal sensation estimation method determination unit 107Aselects the method for estimating the second thermal sensation.

Furthermore, the thermal sensation estimation method determination unit107A may select the method for estimating thermal sensation to be usedon the basis of a result of a comparison between an average surfacetemperature (an example of thermal environment information regarding athermal environment of a person) of the hands 303 of the person 30 and afifth threshold, instead. In this case, if the average surfacetemperature of the hands 303 is equal to or higher than the fifththreshold, the thermal sensation estimation method determination unit107A selects the method for estimating the first thermal sensation. Ifthe average surface temperature of the hands 303 is lower than the fifththreshold, on the other hand, the thermal sensation estimation methoddetermination unit 107A selects the method for estimating the secondthermal sensation.

Modifications

Although the method for estimating thermal sensation and the likeaccording to one or a plurality of aspects have been described on thebasis of the first and second embodiments, the present disclosure is notlimited to the first and second embodiments. The one or plurality ofaspects may also include modes obtained by modifying the first or secondembodiment in various ways conceivable by those skilled in the art andmodes constructed by combining different components in the first andsecond embodiments insofar as the scope of the present disclosure is notdeviated from. For example, the first and second embodiments may becombined with each other.

Although the thermal sensation estimation method determination unit 107(107A) selects either (1) the method for estimating the first thermalsensation or (2) the method for estimating the second thermal sensationas the method for estimating thermal sensation to be used on the basisthermal environment information in the above embodiments, for example,the method used is not limited to these. The thermal sensationestimation method determination unit 107 (107A) may select (1) themethod for estimating the first thermal sensation, (2) the method forestimating the second thermal sensation, or (3) both the method forestimating the first thermal sensation and the method for estimating thesecond thermal sensation as the method(s) for estimating thermalsensation to be used on the basis of thermal environment information,instead. If the thermal sensation estimation method determination unit107 (107A) has selected both the method for estimating the first thermalsensation and the method for estimating the second thermal sensation,the thermal sensation estimation method determination unit 107 (107A)estimates thermal sensation by, for example, weight-averaging a resultof the estimation of thermal sensation by the method for estimating thefirst thermal sensation and a result of the estimation of thermalsensation by the method for estimating the second thermal sensationusing a certain value. For example, two thresholds of A° C. and B° C.(A<B) are used in order to determine a surface temperature C of feet. Ifthe surface temperature C of the feet is lower than A° C., the resultTs2 of the estimation of the second thermal sensation is selected. Ifthe surface temperature C of the feet is higher than B° C., on the otherhand, a result Ts1 of the estimation of the first thermal sensation isselected. If the surface temperature C of the feet falls between A° C.and B° C., a weighted average of the result Ts1 of the estimation of thefirst thermal sensation and the result Ts2 of the estimation of thesecond thermal sensation represented by expression (6) is used as aresult of estimation of thermal sensation.(Ts1×(B−C)+Ts2×(C−A))/(B−A)  (6)

Although the air conditioner is the automotive air conditioner 40 in theabove embodiments, for example, the air conditioner may be a spot airconditioner installed in a room, instead.

Although the vehicle is the automobile 20 in the above embodiments, forexample, the vehicle may be a train, an airplane, or the like, instead.

Although the thermal sensation estimation apparatus 10 (10A) isinstalled in the automobile 20 in the above embodiments, for example,the thermal sensation estimation apparatus 10 (10A) may be installed ina room of a house, instead.

Some or all of the components of the apparatuses may be achieved by anintegrated circuit (IC) card or a separate module removably attached tothe apparatuses. The IC card or the module is a computer systemincluding a microprocessor, a read-only memory (ROM), and arandom-access memory (RAM). The IC card or the module may include asuper-multifunctional large-scale integration (LSI) circuit. When themicroprocessor operates in accordance with a computer program, the ICcard or the module achieves functions thereof. The IC card or the modulemay be tamper-resistant.

The present disclosure may be the above-described methods. The presentdisclosure may be a computer program that achieves these methods using acomputer, or may be a digital signal including the computer program. Thepresent disclosure may be a computer-readable recording medium storingthe computer program or the digital signal, such as a flexible disk, ahard disk, a CD-ROM, a magneto-optical (MO) disk, a digital versatiledisc (DVD), a DVD-ROM, a DVD-RAM, a Blu-ray Disc (BD; registeredtrademark), or a semiconductor memory. The present disclosure may be thedigital signal stored in the recording medium. The present disclosuremay be the computer program or the digital signal transferred through anelectrical communication line, a wireless or wired communication line, anetwork typified by the Internet, datacasting, or the like. The presentdisclosure may be a computer system including a microprocessor and amemory. The memory may store the computer program, and themicroprocessor may operate in accordance with the computer program. Thepresent disclosure may be implemented by another independent computersystem by transferring the program or the digital signal stored in therecording medium or by transferring the program or the digital signalthrough the network or the like.

The present disclosure can be used, for example, for a method forestimating thermal sensation.

What is claimed is:
 1. A vehicle comprising, an air conditioner, and athermal sensation estimation apparatus including: a processor; and amemory that stores a program, wherein the program causes the processorto perform operations including: obtaining thermal environmentinformation at least regarding a thermal environment of or around aperson; estimating a first thermal sensation using a first method on thebasis of the thermal environment information, wherein the first thermalsensation indicates a first degree of warmth or coldness of the person;estimating a second thermal sensation using a second method on the basisof the thermal environment information, wherein the second thermalsensation indicates a second degree of warmth or coldness of the personand wherein the second method is a method different from the firstmethod; selecting at least one of the first thermal sensation estimatedusing the first method and the second thermal sensation estimated usingthe second method on the basis of the thermal environment information;and outputting, to the air conditioner, instruction information usingthe selected at least one of the first thermal sensation estimated usingthe first method and the second thermal sensation estimated using thesecond method, and wherein the instruction information is informationfor controlling the air conditioner.
 2. The vehicle according to claim1, wherein the first method is a method for estimating, as the firstthermal sensation indicating the first degree, thermal sensation basedon an amount of heat lost from the person, and wherein the second methodis a method for estimating, as the second thermal sensation indicatingthe second degree, thermal sensation based on a surface temperature ofthe person.
 3. The vehicle according to claim 2, wherein the thermalenvironment information is a difference between a temperature outside ofthe vehicle in which the person stays and a temperature inside of thevehicle.
 4. The vehicle according to claim 3, wherein the programfurther causes the processor to perform operations including:determining whether the difference is equal to or larger than a firstthreshold; and determining whether a certain period of time elapsesafter the person enters the vehicle, if it is determined that thedifference is equal to or larger than the first threshold, wherein, ifit is determined that the difference is equal to or larger than thefirst threshold and that the certain period of time does not elapse, thesecond thermal sensation estimated using the second method is selectedas the at least one of the first thermal sensation estimated using thefirst method and the second thermal sensation estimated using the secondmethod in the selecting, and wherein, if it is determined that thedifference is equal to or larger than the first threshold and that thecertain period of time elapses, the first thermal sensation estimatedusing the first method is selected as the at least one of the firstthermal sensation estimated using the first method and the secondthermal sensation estimated using the second method in the selecting. 5.The vehicle according to claim 3, wherein the program further causes theprocessor to perform operations including: determining whether thedifference is equal to or larger than a first threshold; anddetermining, if it is determined that the difference is equal to orlarger than the first threshold, whether a difference between thesurface temperature of the person and the temperature inside the vehicleis equal to or larger than a second threshold, wherein, if it isdetermined that the difference between the surface temperature of theperson and the temperature inside the vehicle is equal to or larger thanthe second threshold, the second thermal sensation estimated using thesecond method is selected as the at least one of the first thermalsensation estimated using the first method and the second thermalsensation estimated using the second method in the selecting, andwherein, if it is determined that the difference between the surfacetemperature of the person and the temperature inside the vehicle issmaller than the second threshold, the first thermal sensation estimatedusing the first method is selected as the at least one of the firstthermal sensation estimated using the first method and the secondthermal sensation estimated using the second method in the selecting. 6.The vehicle according to claim 2, wherein the thermal environmentinformation is a surface temperature of the person's feet, wherein theprogram further causes the processor to perform operations including:determining whether the surface temperature of the person's feet isequal to or higher than a third threshold, wherein, if it is determinedthat the surface temperature of the person's feet is equal to or higherthan the third threshold, the first thermal sensation estimated usingthe first method is selected as the at least one of the first thermalsensation estimated using the first method and the second thermalsensation estimated using the second method in the selecting, andwherein, if it is determined that the surface temperature of theperson's feet is lower than the third threshold, the second thermalsensation estimated using the second method is selected as the at leastone of the first thermal sensation estimated using the first method andthe second thermal sensation estimated using the second method in theselecting.
 7. The vehicle according to claim 2, wherein the thermalenvironment information is a temperature around the person's feet,wherein the program further causes the processor to perform operationsincluding, determining whether the temperature around the person's feetis equal to or higher than a fourth threshold, wherein, if it isdetermined that the temperature around the person's feet is equal to orhigher than the fourth threshold, the first thermal sensation estimatedusing the first method is selected as the at least one of the firstthermal sensation estimated using the first method and the secondthermal sensation estimated using the second method in the selecting,and wherein, if it is determined that the temperature around theperson's feet is lower than the fourth threshold, the second thermalsensation estimated using the second method is selected as the at leastone of the first thermal sensation estimated using the first method andthe second thermal sensation estimated using the second method in theselecting.
 8. The vehicle according to claim 2, wherein the thermalenvironment information is a surface temperature of the person's hands,wherein the program further causes the processor to perform operationsincluding, determining whether the surface temperature of the person'shands is equal to or higher than a fifth threshold, wherein, if it isdetermined that the surface temperature of the person's hands is equalto or higher than the fifth threshold, the first thermal sensationestimated using the first method is selected as the at least one of thefirst thermal sensation estimated using the first method and the secondthermal sensation estimated using the second method in the selecting,and wherein, if the surface temperature of the person's hands is lowerthan the fifth threshold, the second thermal sensation estimated usingthe second method is selected as the at least one of the first thermalsensation estimated using the first method and the second thermalsensation estimated using the second method in the selecting.
 9. Thevehicle according to claim 2, wherein the estimating of the firstthermal sensation is performed by calculating a difference between asurface temperature of a human body area, which at least includes a partof the person's body exposed and a part of the person's clothes, and atemperature around the person, calculating an amount of heat lost fromthe person by multiplying the difference by a certain value, andestimating the first thermal sensation on the basis of the amount ofheat lost from the person.
 10. The vehicle according to claim 9, whereinthe surface temperature of the human body area is calculated using athermal image of an area including the person captured by a thermalcamera.
 11. The vehicle according to claim 2, wherein the estimating ofthe second thermal sensation is performed by obtaining a surfacetemperature of a human body area, which at least includes a part of theperson's body exposed and a part of the person's clothes, and estimatingthe second thermal sensation on the basis of a result of a comparisonbetween the surface temperature of the human body area and a sixththreshold.
 12. The vehicle according to claim 11, wherein the surfacetemperature of the human body area is calculated using a thermal imageof an area including the person captured by a thermal camera.
 13. Thevehicle according to claim 1, wherein the program further causes theprocessor to perform operations including, if both of the first thermalsensation estimated using the first method and the second thermalsensation estimated using the second method are selected as the at leastone of the first thermal sensation estimated using the first method andthe second thermal sensation estimated using the second method in theselecting, the selected first thermal sensation and the selected secondthermal sensation using a certain value.
 14. The vehicle according toclaim 1, wherein the instruction information for controlling air volume,air temperature, or wind direction of an air conditioner is output tothe air conditioner on the basis of the selected at least one of thefirst thermal sensation and the second thermal sensation.